1. Field of the Invention
The present general inventive concept relates to a back light unit and an image display device using the same, and more particularly to a back light unit that reflects light which is incident at about a 90° angle and lets light pass through which is incident at a generally acute angle received from a light source and an image display device using the same.
2. Description of the Related Art
Liquid Crystal Displays (LCDs) are light weight, slim, full-color, and are capable of supporting high definition resolution. On account of such advantages, the use of LCDs has been increasing. For instance, LCDs are being used for a variety of display devices, including desktop computers, laptop computers, PDAs, cell phones, and televisions.
Since LCDs do not emit light on their own, a light source like a back light unit is required. Generally, a back light unit comprises a plurality of lamps, a reflection plate which reflects light emitted from the lamps, and a diffuser plate and a diffuser sheet which are used to diffuse light evenly.
Currently, back light units deploy a diffuser plate and a diffuser sheet to reduce the Mura effect, and to adjust the distance between a lamp and a diffuser plate to set an optimum distance so that uniformity of light may be provided without causing the Mura effect.
In order to realize a slim back light unit, the distance between a lamp and a diffuser should be short. However, the shorter the distance is, the more the Mura effect occurs. This problem can be solved by adding lamps to the back light unit. However, adding lamps increases costs.